Closely Spaced Parallel Runways (CSPR) have historically been defined as parallel runways spaced less than 4300 ft. apart, but at least 700 ft. apart. When visual approaches can be conducted, simultaneous arrivals to CSPR are permissible. In visual approaches, simultaneous arrivals to CPSR require that flight crews on both aircraft maintain a visual separation. Runways spaced less than 2500 ft. apart have an additional requirement that flight crews must be aware of wakes produced by neighbor aircraft, and avoid wake encounters (typically by staying above or ahead of the wake of the neighbor aircraft).
When conditions do not permit CSPR visual approaches, instrument approach procedures (IAPB) may be utilized. However, the instruments may have surveillance uncertainties; for example, the angular nature of Instrument Landing System (ILS) localizer guidance may be between 3° and 6° degrees. The uncertainties may compound when used together, such that the two ILS localizers overlap somewhere on the extended final approach, degrading the resolution of the aircraft's position, and the accuracy as distance from the runway increases. As a result, increased separations may be required, which reduces the airport capacity.
To increase capacity during CSPR using the IAP, a flight deck-based solution called Paired Approach procedure (PA) is a standard regulatory solution. The PA procedure is a cooperative procedure enabling instrument dependent approaches to closely spaced parallel runways (CSPR) down to Category I minima (a Category 1 minima is one of several instrument landing system (ILS) categories for providing horizontal and vertical guidance for an aircraft during landing). The PA procedure leverages data from the Automatic Dependent Surveillance-Broadcast (ADS-B) out for the lead aircraft, received by the ADS-B in of the trail aircraft. When two aircraft on CSPR approaches are ‘paired’, Air Traffic Control (ATC) issues a required ASG (assigned spacing goal) to the “trail” aircraft, which is a position within a safe distance (free from turbulence) relative to the ‘target’ aircraft. The trail aircraft has to maintain this position, adding a new task to the pilot's already demanding approach duties. In addition to maintaining the ASG, from the start of the IAP until touchdown, the relative along-track position of the trail aircraft must remain within a forward and rear boundary that avoids an encounter with a wake vortex from the target aircraft.
Accordingly, improvements to paired approach (PA) systems are desirable. Specifically, technologically improved PA systems and methods that provide easily comprehensible, current, visual guidance distinguishing wake boundaries and speed boundaries are desirable. Furthermore, other desirable features and characteristics of the present disclosure will become apparent from the subsequent Detailed Description and the appended claims, taken in conjunction with the accompanying drawings and this Background.